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Date: Thu, 31 Oct 2024 10:21:13 +0100
From: Christoph Hellwig <hch@lst.de>
To: Leon Romanovsky <leon@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Jason Gunthorpe <jgg@ziepe.ca>, Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
	Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Logan Gunthorpe <logang@deltatee.com>,
	Yishai Hadas <yishaih@nvidia.com>,
	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	=?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
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	linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org,
	kvm@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v1 00/17] Provide a new two step DMA mapping API
Message-ID: <20241031092113.GA1791@lst.de>
References: <cover.1730298502.git.leon@kernel.org> <3144b6e7-5c80-46d2-8ddc-a71af3c23072@kernel.dk> <20241031083450.GA30625@lst.de> <20241031090530.GC7473@unreal>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Thu, Oct 31, 2024 at 11:05:30AM +0200, Leon Romanovsky wrote:
> This series is a subset of the series you tested and doesn't include the
> block layer changes which most likely were the cause of the performance
> regression.
> 
> This is why I separated the block layer changes from the rest of the series
> and marked them as RFC.
> 
> The current patch set is viable for HMM and VFIO. Can you please retest
> only this series and leave the block layer changes for later till Christoph
> finds the answer for the performance regression?

As the subset doesn't touch block code or code called by block I don't
think we need Jens to benchmark it, unless he really wants to.